In connection with oil installations on the bottom of the sea, there has been, in the last years, a development where the oil companies demand disconnecting switches and circuit breakers for high voltage and/or current, which can be installed or operated under water.
It is known that a type of medium voltage disconnector or disconnecting switch has been developed and delivered for use under water. Yet this can break and close the electrical circuit in a power-off or voltageless mode.
There are not any pure high voltage circuit breakers for underwater use, from the surface and down to depths as for example 3000-4000 m, or even deeper.